Which of these does not involve a chemical change? a. red delicious apples fell to the ground. b. cocaine causes the release of norepinephrine from nerve cells. c. mercury is used in barometers because it has a high density. d. antacids often an upset stomach

c. Mercury is used in barometers because it has a high density

Explanation:

Chemical change -  

It refers to any change in a chemical process , where there is formation of any new substance , is referred to as a chemical change .

The indication of any chemical change is the formation of some new substance.

Hence, from the question,

The process which does not involve chemical change is  -

The use of mercury in barometer , to measure pressure , in this process no new substance is formed i.e. , now change in mercury.